1. Field of the Invention
The present invention relates to an absorbent article such as sanitary napkin, panty liner and pad for incontinence and, more particularly, it relates to an absorbent article equipped with a surface sheet having good soft feeling, cushioning property and shape retaining property, and to a process for manufacturing the same.
2. Description of the Related Art
Absorbent articles having a liquid-permeable surface sheet at the liquid-receiving side of an absorbent layer are disclosed, for example, in International Unexamined Patent Publication (Kohyou) No. Heisei 10-502000.
Specifically, International Unexamined Patent Publication (Kohyou) No. Heisei 10-502000 discloses a sanitary napkin, in which a cover layer of a corrugated configuration (or wavy shape) is provided on a support layer so that the leakage of the body fluid can be prevented by the wavy shape and the flexibility of the wavy shape can make it comfortable to wear.
However, in the sanitary napkin mentioned above, the wavy shape is apt to be deformed and flattened or fall down sideways by the pressure of the user""s body when the cover layer having the wavy shape touches the skin. In addition, even when the body pressure applied to the wavy shape fluctuates and is lowered upon use, the cover layer hardly restores to the original wavy shape from the flat or fallen state. As a result, the cover layer does not at all times closely touch the skin of the user in an optimum state, and there are problems that the excreted liquid spreads more than necessary on the absorbent article resulting in sideways leakage and that soft feeling to the skin and cushioning property are lowered.
The present invention has an object to provide an absorbent article which can closely contact with the user""s skin at all times and which can retain soft feeling and cushioning property, and also to provide a process for manufacturing the same.
According to the invention, there is provided an absorbent article comprising an absorbent layer and a liquid-permeable surface sheet placed on a liquid-receiving side of the absorbent layer for introducing excreted liquid from the human body to the absorbent layer, wherein the surface sheet is of a corrugated configuration to have valleys and peaks extending in a longitudinal direction of the article and alternately arranged in a transverse direction perpendicular to the longitudinal direction, and wherein each valley has a connecting part raised to connect between two adjacent peaks.
In the absorbent article of the present invention, there is provided the connecting part to connect between the peaks of the surface sheet, so that the peaks are prevented from being flattened or falling down sideways readily by the pressure of user""s body. Even if they are flattened or fall down sideways, in addition, the connecting part can act elastically on the peaks, when the body pressure is lowered, so that the peaks can readily restore to the original shape. That is, even when the body pressure fluctuates due to the movement of the user, the peaks can respond to the movement of the user""s body to be flattened or restore to the original shape, whereby the close contact to the user""s skin can be always maintained in a high level. Accordingly, the excreted liquid hardly spreads on the surface sheet to thereby prevent sideways leakage effectively. In addition, soft and cushiony feeling to the user is not lowered.
For example, the connecting part may connect side slopes of the two peaks. With the connecting part being formed to connect the side slopes of the peaks, the connected side slopes can be readily raised up, when the body pressure having been applied to the peaks is lowered, so that the peaks can readily restore to the original shape.
Preferably, each valley has a plurality of connecting parts arranged at regular intervals in the longitudinal direction. In this case, it is preferred that the interval of the connecting parts in the longitudinal direction is from 5 mm to 30 mm.
With the connecting parts in each valley being arranged at regular intervals in the longitudinal direction, as describer above, restoring ability of the corrugated configuration is improved all over the surface sheet.
Preferably, the connecting parts are staggered in the longitudinal direction, between two adjacent valleys.
With the connecting parts being arranged in such a staggered manner, the connecting parts can easily restore the individual peaks. In addition, the spread of the excreted liquid in the transverse direction is easily prevented.
Preferably, the length in the transverse direction of the top of the connecting part is from 1 mm to 10 mm.
Preferably, the height size (h) from the bottom of the valley to the top of the connecting part falls within a range of 20% to 80% the height size (H) from the bottom of the valley to the top of the peak. Below the lower limit of the aforementioned range, a restoring function of the corrugated configuration by the connecting part is lowered. Above the upper limit of the aforementioned range, on the other hand, the connecting part is apt to touch the skin whereby the feeling upon wear becomes bad.
Preferably, the surface sheet has a lower fiber density in the connecting part than in the valley exclusive of the connecting part. With the connecting part being made in such a low density as above, the excreted liquid, which tends to flow along the valleys and spread, is stopped by the connecting part.
Preferably, the surface sheet has a higher fiber density in the bottom of the valley than in the top of the peak. Also preferably, the surface sheet has a higher fiber density in the top of the peak than in the side of the peak. Also preferably, the surface sheet has a higher fiber density in the top of the peak than in the connecting part and in the side of the peak, and the fiber density in the connecting part is equal to or higher than that in the side of the peak. Most preferably, the relation of the fiber densities in respective parts of the surface sheet is (bottom of valley) greater than (top of peak) greater than (connecting part)xe2x89xa7(side of peak).
As a result of the above, the feeling to the skin and the cushioning property of the surface sheet can be improved. Moreover, the excreted liquid is difficult to spread in the longitudinal and widthwise directions of the valleys, so that leakage from the edges of the article in the longitudinal and transverse directions thereof can be suppressed. Accordingly, the excreted liquid is quickly absorbed by the absorbent layer through the surface sheet whereby little residual liquid remains on the surface sheet and a fresh and dry feeling can be achieved at all times.
Preferably, the back of the surface sheet is fixed to the absorbent layer at the bottom of the valley. In this case, displacement between the surface sheet and the absorbent layer hardly occurs.
Preferably, the surface sheet is a laminate of a plurality of nonwoven fabrics containing hydrophobic fibers. If it is formed by laminating a plurality of bulky nonwoven fabrics, e.g., air-through nonwoven fabrics, the surface sheet will have improved soft feeling and cushioning property.
According to the invention, there is also provided a process for manufacturing an absorbent article, comprising the steps of:
(a) pressing a nonwoven fabric, which is supplied in a predetermined direction, between a first shaping means and a second shaping means to form a surface sheet, and
(b) placing and fixing the surface sheet on a liquid-receiving side of an absorbent layer, wherein
the first shaping means has ribs and grooves extending in the supplying direction of nonwoven fabric and alternately arranged in a transverse direction perpendicular to the supplying direction; the
second shaping means has ribs and grooves extending in the supplying direction and alternately arranged in the transverse direction, each rib of which has a plurality of recesses formed at intervals in the supplying direction; and
the surface sheet formed in the step (a) has peaks each compressed between the rib of the first shaping means and the groove of the second shaping means, valleys each compressed between the groove of the first shaping means and the rib of the second shaping means, and connecting parts raised from the valleys to connect between two adjacent peaks at the part corresponding to the recesses of the second shaping means.